Computation of Net Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Computation of Net Earnings per Share
Net income available to common stockholders	$ 27,515	$ 18,906	$ 16,480	$ 10,785	$ 13,302	$ 11,221	$ 62,901	$ 35,308
Weighted average common shares outstanding used in computing basic income per share	33,537			33,477			33,643	33,159
Incremental options and RSUs	552			697			696	911
Weighted average common shares used in computing diluted net income per share	34,089			34,174			34,339	34,070
Net income per share
Basic	$ 0.82			$ 0.32			$ 1.87	$ 1.06
Diluted	$ 0.81			$ 0.32			$ 1.83	$ 1.04
Anti-dilutive common equivalent shares excluded from calculation	347			848			413	8,226